> It has never been easier to snap together a cross-platform app to do almost anything than it is today
Software engineering is weirdly harder today than it's ever been in many domains.
A cross platform app might have to support iOS, iPadOS, MacOS, Android, Windows, Linux and the Web. Music and Video apps might additionally have to support various flavours of vehicle and TV platforms too.
On the server side your friendly scripting language will probably be running in a venv in a container on a VM on a cloud. Or potentially just a venv locally keeping the containerisation for the cloud.
Back in the day, emails could be sent from my computer to your computer if I knew your IP address. Nowadays my email won't get past your spam filters unless I buy and warm up a reputable domain on a respectable IP address and adhere to the correct content standards. The precise rules for these aren't documented anywhere.